Quick answer. Kidney cancer often causes no symptoms early on and is frequently found by chance on a scan done for another reason. The single most important warning sign is blood in the urine, which should always be checked by a doctor even if it happens only once.
Kidney cancer is a growth that starts in the cells of the kidney, most commonly a type called renal cell carcinoma. Many people in Singapore have no symptoms at all in the early stages, and a fair number of kidney cancers are now picked up incidentally when an ultrasound or CT scan is done for an unrelated complaint. When symptoms do appear they tend to come later, which is why any unexplained blood in the urine deserves prompt assessment.
This guide explains what kidney cancer is, the signs to look out for, the risk factors, how it is diagnosed and the main treatment options used in Singapore. It is general information and not a substitute for a consultation. If you notice blood in your urine or a persistent ache in your side, see a doctor rather than waiting to see if it settles.
At a glance
| Finding | What it can feel or look like | What to do |
|---|---|---|
| Blood in the urine (haematuria) | Pink, red or tea-coloured urine, often painless and may come and go | Always see a doctor, even if it happens once |
| Flank pain | A persistent dull ache in the side or lower back below the ribs | Get it assessed if it is new or ongoing |
| A lump in the side or abdomen | A mass you or a doctor can feel | See a doctor promptly |
| General symptoms | Unexplained weight loss, tiredness, fever or night sweats | Worth a review, especially if combined with other signs |
| No symptoms | Found incidentally on a scan done for another reason | Follow up as advised; many early cancers are found this way |
What is kidney cancer?
The kidneys are two bean-shaped organs that filter waste from the blood and make urine. Kidney cancer happens when cells in the kidney grow out of control and form a tumour. The most common form in adults is renal cell carcinoma, which begins in the lining of the tiny tubes inside the kidney. Less common types include cancers that start in the central collecting area of the kidney.
It is more common in older adults and slightly more common in men than women. In Singapore, as imaging such as ultrasound and CT has become more widely used, an increasing proportion of kidney tumours are discovered early and by chance, before they cause any symptoms. Early-stage kidney cancer that is confined to the kidney is often very treatable.
Symptoms & signs
Early kidney cancer usually causes no symptoms at all. When signs do develop, they may include:
- Blood in the urine (haematuria) – the urine may look pink, red or like weak tea, and it is often painless and may come and go
- A persistent ache or pain in the side, flank or lower back
- A lump or swelling in the side or abdomen
- Unexplained weight loss
- Persistent tiredness or feeling generally unwell
- A fever or night sweats that are not due to an infection
- Loss of appetite
Many of these symptoms are far more often caused by harmless or non-cancerous conditions, such as a urine infection or kidney stones. That does not mean they should be ignored, though – the only way to know the cause is to have them checked.
Causes & risk factors
The exact cause of kidney cancer is not always known, but several factors raise the risk:
- Smoking – one of the strongest and most preventable risk factors
- Being older, with most cases in people over 50
- Obesity and high blood pressure
- Long-term kidney disease, especially in people on long-term dialysis
- A family history of kidney cancer or certain inherited conditions
- Long-term, heavy use of some pain medicines
Having one or more risk factors does not mean you will develop kidney cancer, and many people with the condition have no clear risk factor. Stopping smoking, keeping to a healthy weight and controlling blood pressure are sensible steps that lower the risk.
How it's diagnosed
If kidney cancer is suspected, a doctor will ask about your symptoms, examine you and arrange tests, which may include:
- Urine tests to look for blood and rule out infection
- Blood tests to check kidney function and general health
- Imaging – an ultrasound is often the first scan, followed by a CT or MRI scan, which gives a detailed picture of the tumour and whether it has spread
- Sometimes a biopsy, where a small sample is taken with a needle for examination, though many kidney tumours are diagnosed and treated based on imaging alone
The scans also help the doctor work out the stage of the cancer – how large it is and whether it has spread – which guides treatment.
Treatment options
Treatment depends on the type, size and stage of the cancer and on your overall health. The main approaches are:
- Surgery – the main treatment for cancer confined to the kidney. The surgeon may remove just the tumour with a margin of healthy tissue (partial nephrectomy) or the whole kidney (radical nephrectomy). This is often done using keyhole or robotic techniques.
- Active surveillance – for some small tumours, particularly in older or less fit patients, the tumour may be monitored closely with scans rather than treated immediately.
- Ablation therapies – small tumours may be destroyed using heat or cold through a needle.
- Targeted therapy and immunotherapy – medicines used for advanced or spread cancer to slow its growth and support the body’s immune response.
The right plan is decided together with a specialist, often involving both a urologist and an oncologist. Prices vary widely depending on the procedure and setting, so ask your care team for a clear estimate before treatment.
When to see a doctor & which specialist
Blood in the urine should always be checked by a doctor, even if it happens only once, is painless, and the urine looks normal again afterwards. Do not wait to see if it returns. Other warning signs that warrant a prompt review include a persistent ache in the side, a lump in the abdomen, or unexplained weight loss, tiredness or fever.
If you have heavy bleeding in the urine with clots, severe pain, or you feel very unwell, seek urgent medical care or call 995. For ongoing assessment and treatment of a suspected kidney tumour, the specialist to see is a urologist, who treats conditions of the kidney and urinary tract. If cancer is confirmed and has spread or needs drug treatment, an oncologist will also be involved. You can find specialists through our directories of the best urologists in Singapore and the best oncologists in Singapore.
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- Best Urology Clinics in Singapore — our editorial shortlist
- urology clinics directory
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Sources
- NHS – Kidney cancer
- Mayo Clinic – Kidney cancer
- HealthHub Singapore – Cancer
- SingHealth – Kidney conditions
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